We read with interest the recent research paper by
Tomar, et al. [1] in Indian Pediatrics. We have
following comments and queries:
1. In the present study, authors mentioned that
there was no polymicrobial growth in any of the cultures; what was
the reason for this finding? Most of the studies in neonates report
a frequency of 4% to 25% polymicrobial infections out of all
bloodstream infections [2,3].
2. The results of this study differ from study by
Sarkar, et al. [4], and author attributed it to small sample
size and inclusion of inborn babies only in the study; however, to
us it seems more due to gross differences in rates of culture
positivity in two studies (9.2% vs 46%).
3. In the present study, incidence of candidemia
was very high (one-third of total culture positive infections); is
there any peculiarity in the study population for this heterogeneous
result?
4. Although sending two blood cultures
simultaneously improves diagnostic yield, it will add cost to
patient care, demands more manpower, and will cause more pain to
neonate. The problem of false positivity can be overcome by time to
positivity (TTP) of blood culture. Various studies have given time
to positivity for individual class of organism beyond which it can
be considered as contaminant [5].
References
1. Tomar P, Garg A, Gupta R, Singh A, Gupta NK,
Upadhyay A. Simultaneous two site blood culture in diagnosis of neonatal
sepsis. Indian Pediatr. 2017;54:199-203.
2. Pammi M, Zhong D, Johnson Y, Revell P, Versalovic
J. Polymicrobial bloodstream infections in the neonatal intensive care
unit are associated with increased mortality: A case-control study. BMC
Infect Dis. 2014;14:390.
3. Hall KK, Lyman JA. Updated review of blood culture
contamination. Clin Microbiol Rev. 2006;19:788-802.
4. Sarkar S, Bhagat I, DeCristofaro JD, Wiswell TE,
Spitzer AR. A study of the role of multiple site blood cultures in the
evaluation of neonatal sepsis. J Perinatol. 2005;26:18-22.
5. Biondi EA, Mischler M, Jerardi KE, Statile AM, French J, Evans R,
et al.;for the Pediatric Research in Inpatient Settings (PRIS)
Network. Blood culture time to positivity in febrile infants with
bacteremia. JAMA Pediatr. 2014;168:844-9.